But advocates for a transportation deal vowed Thursday to push the question to the November ballot on their own.

“I can almost guarantee you there will be measures on the ballot,” said Senate President Kevin Grantham, a Cañon City Republican. “The bottom line is we need to fix transportation in this state.”

The roadblock for the transportation bill is conservative opposition in the Republican-led Senate, where three lawmakers on a key committee are poised to defeat the measure because it includes asking voters for a 0.5 percentage-point increase in the state sales tax.

A resigned Grantham, a prime bill sponsor who wagered significant political capital to forge a deal, acknowledged the reality Thursday and sent shock waves through the statehouse on day 100 of the 120-day session.

“At this point, we can’t count to three,” he said, describing the number of votes needed to advance the bill through the Senate Finance Committee next week.

“No matter how you slice it,” he added, “this comes down to a sales tax increase. I’m not sure what ornaments we can hang on this tree that will make that not as important.”

All three Republican committee members, Sens. Tim Neville, Owen Hill and Jack Tate, confirmed they will not support a measure with a tax hike, essentially ensuring the demise of House Bill 1242.

“A new tax is not the way we need to fund this right now,” said Hill, a Colorado Springs lawmaker. Like most GOP opponents, he wants to see current tax dollars go toward transportation — even if it means limiting dollars for other priority areas, such as health care, public safety and education.

“We get a billion new dollars every single year,” he said. “It’s wrong, it’s unfair, to go back and tell taxpayers you have to pay more taxes because we have not been responsible.”

House Speaker Crisanta Duran, a Denver Democrat and bill sponsor, expressed optimism that negotiations will continue, even as she blasted Republicans for their opposition.

“To me what the question is before us is how do we make sure that we have more people who are willing to problem-solve versus people who are willing to put political ideology above all,” Duran told reporters.

“The people who do not want to vote in favor of a transportation-referred measure, they are turning their backs … on all the different organizations that have supported this effort,” she said, standing to unroll a…